Telescope Innovator Shines His Genius On New Fields

Roger Angel, an astronomer at the University of Arizona, stands in front of his new project: a solar tracker. Angel wants to use the device to harness Arizona's abundant sunlight and turn it into usable energy.

Angel uses this rotating furnace at the Steward Observatory Mirror Lab on the University of Arizona campus to make his giant mirrors. The process, called "spin casting," helps form the molten glass into the parabolic shape needed for focusing light.

Roger Angel's mirror technology is now used in many large telescopes around the world, including this one, the Large Binocular Telescope at the Mount Graham International Observatory in Arizona. Its twin mirrors can produce images 10 times sharper than the Hubble Space Telescope.

Angel does a final inspection on one of his mirrors. The weight of telescope mirrors made the traditional way limits their size. Angel realized he could produce a bigger mirror by creating a mold with a honeycomb pattern, making the mirror lighter.

An illustration of Angel's 2006 idea to reduce the effects of global warming by reflecting the sun's light with massive glass shields in space. It's a last-resort sort of idea, Angel admits.

University of Arizona

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Originally published on August 23, 2012 12:23 pm

You may not be familiar with the name Roger Angel, but if there were ever a scientist with a creative streak a mile wide, it would be he.

Angel is an astronomer. He's famous for developing an entirely new way of making really large, incredibly precise telescope mirrors. But his creativity doesn't stop there. He's now turned his attention to solar power, hoping to use the tricks he learned from capturing distant light from stars to do a more cost-efficient job of capturing light from the Sun.

"Roger's always been someone who has lots of wild ideas; some of them are superb, some of them probably not so good. But he's incredibly creative," says Brian Schmidt of the Australian National University in Canberra. "That creativity coupled to sort of a genius is quite rare. So Roger's well-known around the world for having these brilliant insights of how to solve problems."

There's something important you should know about Schmidt: He shared the Nobel Prize in Physics last year for discovering that the expansion of the universe was accelerating. He says most scientists — and he includes himself — aren't the creative problem-solvers Roger Angel is.

"We tend to be the people that close out the game, and you know, do what is obvious and do it well," he says. "Where Roger is the person who really takes you and puts you into a new track and starts new ideas."

The Mirror Man

Angel runs the mirror lab at the University of Arizona in Tucson. I dropped by in January as Angel and his colleagues were about to cast one of their enormous mirrors 25-feet across. The process Angel invented solves a problem that had confounded telescope makers: how to make a mirror that big out of a solid block of glass.

Angel solved the problem with a design the creates a piece of glass with a hollow, honeycomb interior. The process involves loading glass onto a honeycomb-shaped mold in a giant rotating furnace. When the temperature reaches 2,100 degrees Fahrenheit — a point known as high fire — the glass melts and slumps into the mold.

Why a rotating furnace? By rotating, the glass begins to take on the parabolic shape it ultimately needs to have to focus starlight. It takes nearly a year to make one of these giant mirrors. He's made more than a dozen now.

Angel's mind is awash in ideas. For example, in the past decade or so, Angel has been searching for ways to do something about the threat from global warming.

In 2006, he wrote a paper exploring the feasibility of sending a huge glass shield into space and placing it in a spot where it would deflect 2 percent of the sun's rays headed for Earth. Doing that would counteract the warming effects of greenhouse gasses, according to Angel.

It's an ambitious notion. You'd need a shield "a bit less than 2,000 miles across. Pretty big," he says. You'd also need a new launching system to get the shield into space. Traditional rockets wouldn't do. Angel says a kind of magnetic gun that could send up the shield one small piece at a time should do the trick.

"It's always fun working with Roger because he has different ideas about completely unrelated things that he wants to talk to you about. And that's just fun," says James Burge, a colleague of Angel's at the University of Arizona.

Burge says Angel doesn't just have a lot of ideas. "He also has the ability to do the quick calculations or the very quick experiment to be able to see which ideas are good. And that's great. He energizes us with that."

Harnessing The Power Of The Sun

Angel is now turning his energizing energies to energy — solar energy, to be precise. He says his experience with telescope mirrors should help him build cost-effective solar power systems.

"That's what I've been doing for the last few years," says Angel, "[to] try to figure out how to make good-enough mirrors — much lower quality than what we use for astronomy — but good enough to get the sunlight to a decent image, and how to get those mounted so you can point them at the sun without too much steel and cost."

Lowering the cost is key. Right now people don't choose electricity from solar power stations because, for the most part, it's a lot cheaper to get electricity from stations powered by fossil fuels.

Angel took me to an abandoned swimming pool on the University of Arizona campus where he's built a working prototype of his solar power system.

It looks a bit like a giant box kite. A white steel frame holds a 10-foot-square mirror. The frame is mounted on a turret that can track the sun. Angel says that to save money, he uses ordinary window glass with a mirrored surface. He's figured out a way to bend glass panels into the right shape so that the light is concentrated on solar cells. Concentrating the light makes the solar cell more efficient at turning the light energy into electricity.

The prototype makes only a few kilowatts, but Angel told me he has some ideas of how he'd like to use that energy.

"What's the most useful thing you can do with a few kilowatts of power?" he says. "Well, you can charge your rechargeable car, your plug-in Prius. So I'd like to do that. It'd be a real good feeling driving around town, knowing the energy came from the sun."

Copyright 2015 NPR. To see more, visit http://www.npr.org/.

Transcript

STEVE INSKEEP, HOST:

This next story may help us understand how it is that brilliant scientists get their ideas. Scientists, of course, are simply trying to understand the world around them, but doing that requires tremendous leaps of imagination. Today, may a science student can explain the principles that make an airplane fly, but the practical way to do that was a lot less obvious when the Wright Brothers built their flying machine. As for Einstein's theory of relativity, it's hard even today for most of us to comprehend what it is, much less how he thought it up.

Even smaller achievements can be mysterious. How did James Wright dream up Silly Putty? NPR science correspondent has been working on a series that explores the minds and motivations of great scientists and inventors, and today his project, Joe's Big Idea, takes us to one of the most creative scientists alive today.

JOE PALCA, BYLINE: When I started this project, I thought I've got to tell people about Roger Angel. I reported on his work earlier this year, but there's so much more to say. He's an astronomer and he dreams big. He wants to peer back in time to the origins of the universe, to take pictures of planets orbiting distant stars. But before you can do those things, you need a telescope with a mirror big enough to capture the faint light trickling down to Earth from far, far away.

Twenty-five years ago, no one could build such a telescope. The glass you'd need to make a big enough mirror would be too heavy. So Angel thought, hmm, do you really need to make a mirror out a solid piece of glass? Maybe you could make the interior hollow like a honeycomb.

BRIAN SCHMIDT: Roger's always been someone who has lots of wild ideas. Some of them are superb. Some of them probably not so good, but he is incredibly creative.

PALCA: That's astronomer Brian Schmidt from the Australian National University in Canberra.

SCHMIDT: And that creativity coupled to sort of a genius is quite rare. So Roger's, you know, well-known around the world for having these brilliant insights of how to solve problems.

PALCA: Now, there's I've got to tell you about Brian Schmidt. He shared the Nobel Prize in Physics last year for discovering that the expansion of the universe was accelerating. He told me most scientists - and he includes himself here - aren't the brilliant problem-solvers Roger Angel is.

SCHMIDT: We tend to be the people who close out the game, and you know, do what is obvious and do it well. Where Roger is the person who really, you know, takes you and puts you into a new track and starts new ideas.

PALCA: So here's Roger Angel with this great idea for making a large lightweight mirror. But then he had to figure out how to do it, how to make a honeycomb mold, what kind of glass to use, and he had to find just the right temperature to bake the glass at so it would flow into the mold the way he wanted. Angel and his colleagues cast these enormous mirrors in a giant rotating furnace. This furnace looks a bit like an enormous enclosed merry-go-round.

The rotation helps the glass take on the parabolic shape it needs to focus starlight. It takes nearly a year to make one of these giant mirrors, so you want to make sure you get it right. The day I dropped by the University of Arizona last January, the temperature inside the furnace was just about to reach its peak at 2100 degrees Fahrenheit, a point known as high fire. Do you still get excited on the day of high fire, or not so much anymore?

ROGER ANGEL: Well, we've tried to arrange it that I don't get excited at all because if you are worried about something, then you should have done something about it ahead of time, right?

PALCA: Didn't somebody once say that genius is the infinite capacity for taking pains?

ANGEL: Oh, there's always a worry when you have, you know, it's a great big ball of very high temperature glass.

PALCA: Well, I was looking at it more on the positive side. I mean, is it still exhilarating at all?

ANGEL: Yeah. Yeah.

PALCA: Creative? Yes. Diffusive? No. Angel's not just interested in astronomy. In the past decade or so he's been thinking about global warming.

ROBERT SIEGEL, HOST:

Roger Angel has an idea, and as ideas go, this is a pretty big one.

PALCA: I'm not the only one at NPR intrigued by Roger Angel. This is from an interview with Robert Siegel in 2006.

(SOUNDBITE OF ARCHIVED RECORDING)

SIEGEL: His plan is to send a huge glass shield into space, and line it up so that it deflects two percent of the sun's rays bound for the Earth.

PALCA: That would counteract the warming effects of greenhouse gases, according to Angel. How big a shield would you need?

(SOUNDBITE OF ARCHIVED RECORDING)

ANGEL: A bit less than 2,000 miles across, so it's pretty big.

SIEGEL: So something on the order of the United States from the Appalachians to the Rockies would have to...

ANGEL: Something like that.

SIEGEL: ...get up there. And how on Earth could people someday put such a piece of glass up in space?

PALCA: Of course Angel had already thought of that problem. He said a kind of magnetic gun that would launch the shield in small segments would do the trick. James Burge is a colleague of Angel's at the University of Arizona. Burge told me the thing about Roger Angel is that he doesn't just have a lot of ideas...

JAMES BURGE: He also has the ability to do the quick calculations or the very quick experiment to be able to see which ideas are good.

PALCA: Even Roger Angel will tell you that a 2,000-mile-wide glass shield is probably only going to be considered as a last resort. He hopes to prevent that day from ever coming, so he's begun to think about alternatives to burning fossil fuels. Now, Angel's a guy who knows all about capturing light, so solar energy was an obvious choice. There are plenty of systems out there that use mirrors to concentrate sunlight for electricity. The problem with all these systems is they're too darn expensive. They can't compete with low-cost electricity made from fossil fuel. Angel hopes to change that.

ANGEL: So that's what I've been doing for the last few years, is trying to figure out how to make good enough mirrors, you know, much lower quality than what we use for astronomy, and how to get those mounted so you can point them at the sun without too much steel and cost.

PALCA: To show me what he's up to, Angel took me over to an abandoned outdoor swimming pool on the University of Arizona campus where he's building a working prototype of his solar power system. It looks a bit like a giant box kite. A huge white steel frame holds a 10-foot square mirror. The frame is mounted on a turret that can track the sun. Angel has found clever ways to use bargain basement materials to keep down costs.

The mirrors are made from cheap mass-produced window glass. They're bent into the right shape using a second-hand industrial oven. A ball of pure glass helps keep the sunlight evenly distributed on the photovoltaic cells that make the electricity. The prototype in this swimming pool only makes a few kilowatts, but Angel told me he has some ideas of how he'd like to use that energy.

ANGEL: What's the most useful thing you can do with a few kilowatts of power? Well, you can charge your rechargeable car, your plug-in Prius. So I'd like to do that. It would be a real good feeling to be driving around town knowing the energy came from the sun.

PALCA: After a while I found myself wondering how Angel has such a knack for solving problems that stumped others, so I asked. Where do your ideas come from? Did you have an idea already today of some solution to a problem you've been thinking about?

ANGEL: Yeah. Ideas, I don't know what it is. I never have to sit down and think, well, I need to have an idea or anything. They just come pouring in.

PALCA: Maybe I shouldn't have been surprised that Roger Angel can't articulate where his ideas come from. It's probably like asking a fish where water comes from. I'd bet a world without ideas is just about impossible for Roger Angel to imagine. Joe Palca, NPR News. Transcript provided by NPR, Copyright NPR.